In recent years, illumination devices using a plurality of light-emitting diodes as light source have been put into practical use. The illumination devices of this type are used as, for example, surface-mounted general lighting which is directly mounted on the indoor ceiling. For example, a conventional illumination device disclosed in Jpn. Pat. Appln. KOKAI Pub. No. 2009-54989 comprises a base member, and a plurality of light-emitting devices mounted on the base member. Each light-emitting device has a substrate formed of ceramics, and a plurality of light-emitting diodes. The light-emitting diodes are fixed to the substrate with adhesive made of epoxy resin.
On the other hand, in light-emitting devices using light-emitting diodes as light source, it is desired to efficiently take light emitted by the light-emitting diodes out of the light-emitting device. To satisfy the demand, known is a conventional light-emitting device having a structure in which a plurality of pads, on which light-emitting diodes are mounted, are provided on the substrate, and surfaces of the pads are covered with a light-reflecting layer. The light-reflecting layer is formed on the surfaces of the pads by subjecting the pads to electroplating.
Electroplating has advantages of good close contact of metal coating with product to be treated, and inexpensive manufacturing cost. In the light-emitting device, however, since a plurality of pads are arranged at intervals on the substrate, when the pads are subjected to electroplating, it is necessary to electrically connect the pads by a dedicated conductor pattern, and maintain all the pads at the same potential.
In addition, the conductor pattern becomes redundant after electroplating is finished. Therefore, it is necessary to perform work in which the conductor pattern is removed from the substrate by boring a number of holes in the substrate along the conductor pattern, and electrical connection between the pads by the conductor pattern is severed. The work of boring holes in the substrate has a large number of steps, and requires much time and labor. This decreases productivity and increases the cost of producing the light-emitting device.